Added licence header in the replace module

replace.py

+# -*- coding: utf-8 -*-
+##############################################################################
+#
+#    Email marketing click & read tracker
+#    Copyright (C) 2011 Florent Aide, <florent.aide@gmail.com>
+#    Copyright (C) 2011 XCG Consulting (http://www.xcg-consulting.fr/)
+#
+#    This program is free software: you can redistribute it and/or modify
+#    it under the terms of the GNU Affero General Public License as
+#    published by the Free Software Foundation, either version 3 of the
+#    License, or (at your option) any later version.
+#
+#    This program is distributed in the hope that it will be useful,
+#    but WITHOUT ANY WARRANTY; without even the implied warranty of
+#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+#    GNU Affero General Public License for more details.
+#
+#    You should have received a copy of the GNU Affero General Public License
+#    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+##############################################################################
 __author__ = 'faide'
 
 import uuid